Farmers find it desirable to tank mix formulated commercial herbicides in the field. The reasons for this desirability may include a need to enhance efficacy through a synergistic response, or the desire to control different kinds of weeds. In addition, mixing formulated herbicides may allow greater weed control, while overall using less active ingredients. Further, it might be desirable to tank mix a formulated insecticide, or other pesticides, with a formulated herbicide. In short, the greater flexibility to tank mix formulated products, the more ability a farmer has to adapt available resources to combat new and existing problems.
Formulated pesticidal mixtures comprising two different active ingredients, wherein one of the commercial formulations contain a cationic surfactant and the other contains an anionic surfactant, can present a special problem. Sometimes said mixtures result in formation of a precipitate or sediment due to the incompatibility of the surfactants. The resulting precipitates make spraying the mixtures quite problematic. Agglomerated mixtures do not flow properly, and tend to clog spray rigs, hoses and nozzles. The term pesticide may include herbicide, insecticide, fungicide or biocide.
U.S. Pat. No. 4,446,042 describes an invention which relates to laundry detergent compositions containing nonionic surfactants, quaternary ammonium cationic surfactants and selected anionic brighteners. The selection of suitable brighteners for detergents containing nonionic and cationic surfactants is problematic since many conventional brighteners are anionic in nature and tend to form insoluble complexes with the quaternary ammonium cationic surfactants. This surfactant compatibility problem is discussed and solved with certain stilbene disulfonate anionic brighteners.
Another area where this type of compatibility problem exists is in the area of dyeing or printing. In U.S. Pat. No. 4,270,916 cationic or certain anionic dyes are rendered compatible with normally incompatible anionic polymers by the addition of nonionic, amphoteric or anionic surface active agents. Examples of such polymers are algin, xanthan gum, S-7 gum polyacrylic acid or polymethacrylic acid. Among the various types of nonionic detergents are condensation products of ethylene oxide with fatty acids, condensation products of ethylene oxide with fatty alcohols, condensation products of ethylene oxide with fatty amines or fatty amides and condensation products of ethylene oxide with phenolic compounds. Among the various anionic surfactants are aliphatic fatty condensate with ethylene oxide, the sodium salt of oleyl sarcoside and condensation product of fatty acids and proteins.
U.S. Pat. No. 4,966,728 relates to adjuvants for postemergent herbicides which are crop oil concentrates. The crop oil concentrates of that invention enhance the activity obtained with other commercial adjuvants. The adjuvant mixtures are suitable for cyclohexanone-type herbicides. The crop oil concentrates of that invention comprise, a mixture of: a) a first active component which is a low foaming nonionic surfactant; b) an anionic surfactant derived from esterification of a polyoxyalkylene nonionic surfactant with a dihydric or trihydric inorganic acid or by carboxylation with an organic acid derivative; and c) optionally a third active component which is a lower alkanol ester of a long chain fatty acid and d) a fourth component of a hydrocarbon "oil".
U.S. Pat. No. 5,084,087 describes an invention relating to adjuvants for postemergent herbicides which fall into the category of crop oil concentrates. The crop oil concentrates of that invention comprise a mixture of: a) one or more herbicides selected from the group consisting of diphenylether herbicides, phenoxyphenoxy herbicides, imidazoline herbicides and cyclohexenone herbicides b) an emulsifier component which is a combination of (i) a polyoxyalkylene nonionic surfactant having an HLB of from 10 to 14 and (ii) an anionic surfactant selected from the group consisting of the dialkyl metal sulfosuccinates and the metal alkylbenzene sulphonates; c) optionally a second surface active component which is a low foaming polyoxyalkylene nonionic surfactant having an HLB of less than 10; and d) a lower alkanol ester of a long chain fatty acid. As an additional component, a hydrocarbon oil may be added.
The present invention relates to the addition of a nonionic surfactant, also called a compatibility agent, which renders compatible mixtures of normally incompatible formulated pesticides, preferably herbicides. It is an object of the present invention to provide an agent for making combined pesticidal compositions compatible, said composition comprising at least one formulated pesticidal composition containing a cationic surfactant, and at least one formulated pesticidal composition containing an anionic surfactant. Another object of the present invention is to prevent the formation of a precipitate or sediment in mixtures of pesticides containing cationic and anionic surfactants normally incompatible with each other. A further object is to provide a stable pesticidal mixture containing at least one cationic surfactant and at least one anionic surfactant. A still further object of the present invention is a method of controlling undesirable vegetation with said combined compatible pesticidal compositions.